Oppai Baka: Oppai Igai wa Mitomenai!!

Youta is a high school student who moves back to his hometown, only to find that everything has changed. The residential areas are now divided by breast cup sizes, and breasts have become the center of society. He must navigate this bizarre new world where chest size determines one's place in life.

As Youta adjusts to this reality, he encounters various challenges and situations that revolve around the obsession with breasts. The story follows his experiences in a town where oppai (breasts) dictate social status and daily life, leading to comedic and risqué encounters.